Oil production and subsidence

During the EIR Scoping Meeting on July 24th and in a follow-up letter to the Beach Reporter, people expressed their concern that E&B’s production operations could result in surface subsidence. This important issue is addressed by E&B’s proposed development plan through produced water re-injection and monitoring of surface elevations at 15 locations in Hermosa Beach and 4 additional locations in surrounding cities.   

Subsidence from oil operations at the nearby Wilmington Field is the most often cited cause of concern.  The subsidence bowl resulting from oil production operations at the Wilmington Field beginning in 1932 and exacerbated by groundwater production by the Naval Shipyard during WW2 famously reached a maximum of 29’ recorded nearly two miles to the west of downtown Long Beach in the 1950’s.  Subsidence at the Wilmington Field was stopped by water injection into the oil formations replacing lost fluids and pressure. 

The occurrence of subsidence in the Long Beach Harbor area resulted in the California Subsidence Act of 1958.  This act states that re-pressuring subsurface oil and gas formations under the supervision of the State Oil and Gas Supervisor will “tend to arrest or ameliorate subsidence.”  Additionally, the California Coastal Act of 1997 also mandates that oil and gas development “not cause or contribute to subsidence hazards unless it is determined that adequate measures will be undertaken to prevent damage from that subsidence.” 

That these acts and practices have been effective is proved by the development of the Wilmington Field extension under Long Beach Harbor by a consortium of five companies (THUMS Long Beach Company) beginning in 1965.  The development plan included replacement of produced fluid volumes by water injection from the very start of operations and has resulted in a stable surface in Long Beach that has not subsided even though over one billion barrels of oil and nine billion barrels of water have been produced by THUMS to date. In addition to the State Oil and Gas Supervisor, the oil production operations are closely monitored and controlled by the City of Long Beach to ensure that subsidence caused by oil extraction will not occur again. 

The City of Long Beach’s website at http://www.longbeach.gov/oil/subsidence/story.asp details the full story of subsidence in the Wilmington Field and the measures employed to successfully mitigate it, ensuring the stability of surface elevations in Long Beach.   

A detailed discussion of subsidence, its causes and E&B’s monitoring and mitigation plan can be found in Appendix H of E&B’s Planning Application.

-Rick Finken